Optical networks are used to deliver services to multiple network subscribers using one or more optical fibers. The optical networks deployed to deliver the services may be passive or active. In a passive optical network (PON), for example, passive optical splitters and combiners enable multiple subscribers to share the same optical fiber. Thus, the PON functions as a point-to-multipoint network. A PON may conform to any of a variety of PON standards, such as the broadband PON (BPON) standard (ITU G.983), the gigabit-capable PON (GPON) standard (ITU G.984), Ethernet PON (EPON) standard (IEEE 802.3), and gigabit-EPON (GEPON) standard, as well as future PON standards under development by organizations such as the Full Service Access Network (FSAN) Group. In an active optical network, such as an active Ethernet optical network, the optical network operates as a point-to-point network. When fiber reaches a premise where one or more subscriber devices are located, the service is commonly referred to as Fiber to the Premises (FTTP).
In FTTP services, an optical network terminal (ONT) terminates an optical fiber that extends to a subscriber premise, such as a business or enterprise, and connects the subscriber devices, such as public branch exchange (PBX) devices, routers, or other subscriber devices to the optical network. The ONT delivers the signals on the optical fiber to the subscriber devices to provide the FTTP services, and receives signals from the subscriber devices and transmits the signals upstream via the optical network. In this manner, the ONT may support a wide variety of services, such as digital signal-1 (commonly referred to as “T1”) services, over the optical network.
Typically, the optical network couples to a network, such as a wide area network (WAN), a metropolitan area network (MAN) or the like, that interconnects one or more optical networks together and may also interconnect these optical networks to a public network, such as the Internet. The WAN may be referred to as a backbone network because it interconnects or provides the backbone to support delivery of information for a plurality of networks, such as the optical network. The backbone network may use any of a variety of transports to transfer information to and from the optical network. For example, the backbone network may comprise a network that implements synchronous optical networking (SONET) and that transports the information to and from the optical network using a legacy transport, such as an asynchronous transport mode (ATM) or ATM transport. As another example, the backbone network may transport information to and from the optical network using next generation transport, such as an Ethernet transport. Next generation Ethernet transports may better utilize the bandwidth of the underlying fiber links of the backbone networks. As a result of the bandwidth gains, the Ethernet transport is quickly emerging as the transport of choice for the backbone network.